Light emitting device, method of manufacturing covering member, and method of manufacturing light emitting device

ABSTRACT

A method of manufacturing a covering member includes providing a first light-reflective member having a through-hole, the through-hole having first and second openings; arranging a light-transmissive resin containing a wavelength-conversion material within the through-hole; distributing the wavelength-conversion material predominantly on a side of the first opening of the through-hole within the light-transmissive resin; and after the distributing of the wavelength-conversion material, removing a portion of the light-transmissive resin from a side of the second opening of the through-hole.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Japanese Patent Application No.2015-109807 filed on May 29, 2015 and Japanese Patent Application No.2016-31940 filed on Feb. 23, 2016. The entire disclosures of JapanesePatent Application No. 2015-109807 and Japanese Patent Application No.2016-31940 are incorporated by reference herein.

BACKGROUND

The present disclosure relates to a light emitting device, a method ofmanufacturing a covering member, and a method of manufacturing the lightemitting device.

In recent years, light-emitting diodes have been used in various formsin the fields of general illumination, vehicle-mounted illumination, andthe like, with the improvement of their qualities.

For example, a light emitting device is known in which a plate-shapedoptical member including an outer frame is disposed over alight-emitting element to be thinned. (see JP 2012-134355 A.)

SUMMARY

Light emitting devices are required to be much thinner than theconventional ones.

It is an object of certain embodiments of the present invention toprovide a light emitting device that can be thinned, a method ofmanufacturing the same, and a method of manufacturing a covering member.

A method of manufacturing a covering member according to one embodimentof the present invention includes: providing a first light-reflectivemember having a through-hole; arranging a light-transmissive resincontaining a wavelength-conversion material within the through-hole;distributing the wavelength-conversion material predominantly on a sideof one opening of the through-hole within the light-transmissive resin;and after the distributing of the wavelength-conversion material,removing a portion of the light-transmissive resin from a side of theother opening of the through-hole.

A light emitting device according to one embodiment of the presentinvention includes: a covering member including a first light-reflectivemember having a through-hole and a light-transmissive resin disposed inthe through-hole; a light-emitting element arranged to face thelight-transmissive resin; and a second light-reflective member arrangedto face the first light-reflective member around the light-emittingelement, the second light-reflective member covering a lateral surfaceof the light-emitting element. The light-transmissive resin contains awavelength-conversion material distributed predominantly on a side of alower surface of the light-transmissive resin facing the light-emittingelement, or predominantly on a side of an upper surface of thelight-transmissive resin, the side of the upper surface apart from thelight-emitting element.

According to certain embodiments of the present invention, a lightemitting device that can be thinned can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic plan view showing a method of manufacturing acovering member in a method of manufacturing a light emitting deviceaccording to a first embodiment.

FIG. 1B is a schematic cross-sectional view taken along the line B-B ofFIG. 1A.

FIG. 2A is a schematic cross-sectional view showing a state in which afirst light-reflective member is held when punching is performed in themethod of manufacturing the covering member according to the firstembodiment.

FIG. 2B is a schematic cross-sectional view showing a state in which anupper die is driven into a first light reflective member when thepunching is performed in the method of manufacturing the covering memberaccording to the first embodiment.

FIG. 2C is an enlarged view of a portion enclosed by a dotted line ofFIG. 2B.

FIG. 3A is a schematic cross-sectional view of a state in whichlight-transmissive resin containing a wavelength-conversion material isdisposed in through-holes of the first light-reflective member in themethod of manufacturing the covering member according to the firstembodiment.

FIG. 3B is a schematic cross-sectional view of a state in which thewavelength-conversion material is eccentrically distributed within thethrough-holes of the first light-reflective member in the method ofmanufacturing the covering member according to the first embodiment.

FIG. 3C is a schematic cross-sectional view of a state in which thelight-transmissive resin and the first light-reflective member arepartially removed in the manufacturing method for the covering memberaccording to the first embodiment.

FIG. 4A is a schematic cross-sectional view showing a state in whichlight-emitting elements are fixed in the method of manufacturing thelight emitting device according to the first embodiment.

FIG. 4B is a schematic cross-sectional view showing a state in which asecond light-reflective member is formed in the method of manufacturingthe light emitting device according to the first embodiment.

FIG. 4C is a schematic cross-sectional view showing a state in which thesecond light-reflective member is formed in the case of including abonding member in the method of manufacturing the light emitting deviceaccording to the first embodiment.

FIG. 4D is a schematic cross-sectional view showing a state in which thesecond light-reflective member is formed to embed electrodes of thelight-emitting elements in the method of manufacturing the lightemitting device according to the first embodiment.

FIG. 5A is a schematic plan view showing cutting lines for separatinginto the light emitting devices in the method of manufacturing the lightemitting device according to the first embodiment.

FIG. 5B is a schematic cross-sectional view taken along the line C-C ofFIG. 5A.

FIG. 6A is a schematic plan view showing the individual light emittingdevices after singulation in the method of manufacturing the lightemitting device according to the first embodiment.

FIG. 6B is a schematic cross-sectional view taken along the line D-D ofFIG. 6A.

FIG. 6C is a schematic cross-sectional view showing a modified exampleof the singulation in the method of manufacturing the light emittingdevice according to the first embodiment.

FIG. 7A is a schematic cross-sectional view showing a state in which afirst light-reflective member with recesses is formed over a supportmember in a method of manufacturing a covering member according to asecond embodiment.

FIG. 7B is a schematic cross-sectional view showing a state in which alight-transmissive resin containing a wavelength-conversion material isdisposed in the recesses in the method of manufacturing the coveringmember according to the second embodiment.

FIG. 7C is a schematic cross-sectional view of a state in which thewavelength-conversion material is eccentrically distributed in thelight-transmissive resin within the recesses in the method ofmanufacturing the covering member in the second embodiment.

FIG. 7D is a schematic cross-sectional view showing a state in which thesupport member on the first light-reflective member is removed and thenbonded to the opposite surface of the first light-reflective member inthe method of manufacturing the covering member according to the secondembodiment.

FIG. 7E is a schematic cross-sectional view showing a state in which thefirst light-reflective member is removed to allow the recesses topenetrate the first light reflective member in the method ofmanufacturing the covering member according to the second embodiment.

FIG. 8A is a schematic plan view of a light emitting device according toa fourth embodiment.

FIG. 8B is a schematic cross-sectional view taken along the line A-A ofFIG. 8A.

FIG. 9 is a schematic cross-sectional view of a light emitting deviceaccording to a fifth embodiment.

FIG. 10 is a schematic cross-sectional view of a light emitting deviceaccording to a sixth embodiment.

FIG. 11 is a schematic cross-sectional view of a light emitting deviceaccording to a seventh embodiment.

FIG. 12 is a schematic cross-sectional view of a light emitting deviceaccording to an eighth embodiment.

FIG. 13A is a schematic cross-sectional view of a light emitting deviceaccording to a first modified example of the eighth embodiment.

FIG. 13B is a schematic cross-sectional view of a light emitting deviceaccording to a second modified example of the eighth embodiment.

FIG. 13C is a schematic cross-sectional view of a light emitting deviceaccording to a third modified example of the eighth embodiment.

FIG. 14A is a schematic cross-sectional view of a light emitting deviceaccording to a ninth embodiment.

FIG. 14B is a schematic cross-sectional view of a light emitting deviceaccording to a modified example of the ninth embodiment.

FIG. 15A is a schematic cross-sectional view of a light emitting deviceaccording to a tenth embodiment.

FIG. 15B is a schematic cross-sectional view of a light emitting deviceaccording to a modified example of the tenth embodiment.

DETAILED DESCRIPTION

Embodiments of the present invention will be described in detail belowwith reference to the accompanying drawings. In the description below,the terms (e.g., upper, lower, and other words including these words)indicative of specific directions or positions are used as appropriate.The use of these terms is for ease of understanding of the presentinvention with reference to the drawings, and does not limit thetechnical range of the present invention by their meanings. The samereference characters represented through the drawings denote the sameparts or members.

First Embodiment

A method of manufacturing a light emitting device in the firstembodiment will be described with reference to FIGS. 1A to 6C.

The method of manufacturing a light emitting device in the firstembodiment includes the steps of:

(1) manufacturing a covering member that includes a firstlight-reflective member having a plurality of through-holes, alight-transmissive resin arranged in each through-hole to havesubstantially the same thickness as the first light-reflective member,and a wavelength-conversion material contained in the light-transmissiveresin to be distributed predominantly on a side of one opening of thethrough-hole;

(2) fixing light-emitting elements over the respectivelight-transmissive resins provided in the through-holes;

(3) forming a second light-reflective member between the adjacentlight-emitting elements provided on or over the light-transmissiveresin; and

(4) separating the individual light emitting devices by cutting thefirst light-reflective member and the second light-reflective member inbetween these adjacent light-emitting elements.

In the method of manufacturing a light emitting device in the embodimentdescribed above, the coating material including the light-transmissiveresin is used to manufacture the light emitting device; thelight-transmissive resin contains the wavelength-conversion materialdistributed predominantly on one opening side of the through-hole. Withthis method, a thin light emitting device can be manufactured.

The method of manufacturing the light emitting device in the presentembodiment will be specifically described below.

Fabrication of Covering Member

Referring to FIGS. 1A to 3C, steps of manufacturing a covering member 70in this embodiment will be described below. The covering member 70fabricated in these steps of manufacturing includes a firstlight-reflective member 10 and a light-transmissive resin 30 containinga wavelength-conversion material 20.

Step 1-1. Preparation of the First Light-Reflective Member withThrough-Holes

The first light-reflective member 10 with through-holes 106 is prepared.The through-hole 106 penetrates a first surface 101 of the firstlight-reflective member 10 and a second surface 102 which is opposite tothe first surface (see FIGS. 1A and 1B). Note that only one through-hole106 may be formed in the first light-reflective member 10, oralternatively a plurality of through-holes 106 may be formed therein.

To form the through-holes 106 in the first light-reflective member 10,any method known in the art may be used. Examples of the formationmethod include irradiation or drawing using laser beam, punching,etching, blasting, and the like. The through-hole 106 preferably has aprotrusion 103 at its sidewall. The protrusion can enhance an adhesiveforce between the light-transmissive resin 30 and the firstlight-reflective member 10 as described below. In the case of usingresin or metal for the first light-reflective member 10, forming thethrough-holes 106 by punching allows the protrusion 103 to be easilyformed on the sidewall of the through-hole 106. That is, duringpunching, as shown in FIG. 2A, the first light-reflective member 10 isvertically held by a holding member 91 and a lower die 92. The upper die90 is pressed downward to the first light-reflective member held in thisway, so that the through-hole 106 in the first light-reflective member10 is formed. At this time, control of a distance of a gap d between theupper die 90 and the lower die 92 allows for forming the protrusion 103at a predetermined position. The gap d between the upper die 90 and thelower die 92 corresponds to a distance between the upper die 90 and thelower die 92 in the X direction (horizontal direction) in FIG. 2A. Forexample, the gap d is adjusted at the time of forming the through-hole106 from the upper to lower direction, which can form the protrusion 103as a protruding portion (obliquely formed) that protrudes downward (seeFIGS. 2B and 2C). In other words, the protrusion 103 may be inclineddownward. This is because the position of the first light-reflectivemember 10 to which a force is applied from the upper die 90 is distantfrom the position to which a force is applied from the lower die 92, bythe gap d between the upper die 90 and the lower die 92. Adjustment ofthe distance of the gap d can also form the through-hole with aplurality of protrusions 103 at the sidewalls thereof. The gap d betweenthe upper die 90 and the lower die 92 may have an appropriate distance,but is preferably in a range of 1 to 30 μm to form an inclinedprotrusion, and preferably in a range of 0 to 30 μm (excluding 0) toform a plurality of protrusions. Furthermore, the distance of the gap dbetween the upper and lower dies 90 and 92 relative to the thickness ofthe first light-reflective member 10 is preferably in a range of 1 to30% to form an inclined protrusion, and preferably in a range of 0 to30% (excluding 0%) to form a plurality of protrusions.

Note that the first light-reflective member 10 with the through-hole 106may be formed by compression molding, transfer molding, injectionmolding, etc., that use a mold. The formation of the firstlight-reflective member 10 in this way can suppress variance in shape ofthe first light-reflective member 10 with the through-holes 106.

After preparing the first light-reflective member 10 with thethrough-holes 106 is prepared, the first light-reflective member 10 withthe through-holes is placed on a support member 80 made of aheat-resistant sheet or the like.

Step 1-2. Arranging of a Light-Transmissive Resin 30 Containing theWavelength-Conversion Material 20

Next, the light-transmissive resin 30 containing wavelength-conversionmaterial 20 is arranged within each through-hole 106 (see FIG. 3A). Toarrange the light-transmissive resin 30 containing thewavelength-conversion material 20, any method known in the art may beused. The known methods include printing, potting, etc. Note that thelight-transmissive resin 30 should be in a state of making thewavelength-conversion material 20 movable within the light-transmissiveresin 30. That is, the light-transmissive resin 30 may be in the liquidstate before curing, or in a semi-cured state. The light-transmissiveresin 30 in the liquid state is preferable as it makes it easier for thewavelength-conversion material 20 to move therein, compared to that inthe semi-cured state. Further, a light diffusion material may becontained in the light-transmissive resin 30.

Step 1-3. Distributing the Wavelength-Conversion Material 20

The wavelength-conversion material 20 is distributed predominantly onthe first surface 101 side within the light-transmissive resin 30 due tospontaneous precipitation or forced precipitation (see FIG. 3B).Examples of the forced precipitation includes centrifugal sedimentationthat precipitates the wavelength-conversion material 20 due to thecentrifugal force generated by the rotation. After precipitating thewavelength-conversion material 20, the light-transmissive resin 30 iscured by heating or the like. As a result, the light-transmissive resin30 in which the wavelength-conversion material 20 is distributedpredominantly on the first surface 101 side is obtained. Note that inthe case where the light diffusion material is contained in thelight-transmissive resin 30, it may be unevenly distributed in the samemanner as the wavelength-conversion material 20. However, the lightdiffusion material is preferably dispersed uniformly without beingunevenly located in the light-transmissive resin 30.

Step 1-4. Removal of the First Light-Reflective Member and theLight-Transmissive Resin

Upper parts of the first light-reflective member and thelight-transmissive resin that are located above the dashed line Ct-Ct ofFIG. 3B are removed. That is, the “first light-reflective member 10 onthe second surface side” and the “light-transmissive resin 30 on theside opposite to the side where the wavelength-conversion material 20 ispredominantly distributed” are removed (see FIG. 3C). To remove thefirst light-reflective member 10 and the light-transmissive resin 30,any method known in the art can be used. Examples of the method forremoving can include etching, cutting, grinding, polishing, blasting,and the like. Thus, the light-transmissive resin 30 can be thinnedwithout substantially changing the content of the wavelength-conversionmaterial 20. That is, the thinned covering member 70 can be obtained. Atthe time of removing the first light-reflective member and thelight-transmissive resin by the etching, cutting, grinding, polishing,blasting, or the like, the “first light-reflective member 10 on thesecond surface side” and the “light-transmissive resin 30 on the sideopposite to the side where the wavelength-conversion material 20 ispredominantly distributed” may have rough surfaces. Roughing thesesurfaces leads to reduction of the tackiness (adhesion) thereof, whichcan make it easier to handle them, for example, at the time of mounting.

Here, in the present specification, regardless of before or after theremoval of the light-transmissive resin 30 or the like, the surface ofthe first light-reflective member 10 where the wavelength-conversionmaterial 20 is predominantly distributed is referred to as a “firstsurface”, while the surface opposite to the first surface is referred toas a “second surface”.

Through the steps mentioned above, the covering member 70 held by thesupport member 80 can be obtained.

Fabrication of the Light Emitting Device

Step A-1. Fixing of the Light-Emitting Element 40

The light-emitting element is fixed onto the light-transmissive resin 30of the covering member 70 manufactured by the above-mentioned method(see FIG. 4A). For example, the light-transmissive resin 30 and a lightextraction surface 401 of the light-emitting element 40 are bondedtogether via a bonding member 60 (see FIG. 4C). Even in the case wherethe light-transmissive resin 30 is not adhesive, the use of the bondingmember 60 allows for bonding the light-emitting element 40 to thelight-transmissive resin 30. The bonding member 60 is preferably formedup to the lateral surfaces of the light-emitting element 40, thusimproving the adhesive force between the light-emitting element 40 andthe light-transmissive resin 30. Note that the surface of thelight-transmissive resin 30 where the wavelength-conversion material 20is predominantly distributed may be bonded to the light extractionsurface 401 of the light-emitting element 40. Alternatively, a surfaceof the light-transmissive resin 30 opposite to the surface thereof wherethe wavelength-conversion material 20 is predominantly distributed maybe bonded to the light extraction surface 401 of the light-emittingelement.

Step A-2. Formation of a Second Light-Reflective Member

A second light-reflective member 50 is formed to cover portions of thelateral surfaces of the light-emitting element 40 and the firstlight-reflective member 10 (see FIG. 4B). The second light-reflectivemember 50 is bonded to the first-reflective member 10 around thelight-emitting element 40. In the case where the light-emitting element40 and the light-transmissive resin 30 are bonded together by using thebonding member 60, the second light reflective member 50 may cover thebonding member 60 (see FIG. 4C). Further, a portion of an electrodeformation surface 402 of the light-emitting element 40 that is notcovered by the electrodes 43 and 44 may be covered by the secondlight-reflective member 50. In this case, the thickness of the secondlight-reflective member 50 (the dimension thereof in the Z direction)may be adjusted to expose parts of the electrodes 43 and 44 from thesecond light-reflective member 50. That is, when the first surface 101of the first light-reflective member 10 is used as the basis for aheight, the height of the second light-reflective member 50 up to thesurface 52, which is opposite to the surface of the secondlight-reflective member 50 facing the first light-reflective member 10,may be equal to or lower than the height of each of the exposed surfaces431 and 441 of the electrodes 43 and 44.

The second light-reflective member 50 may be formed in the thicknessthat embeds therein the electrodes 43 and 44 (see FIG. 4D). Thereafter,the part of the second light-reflective member 50 above the dashed lineCt-Ct of FIG. 4D is removed. That is, a portion of the secondlight-reflective member 50 may be removed to expose the electrodes 43and 44. To remove the second light-reflective member 50, any methodknown in the art may be used. Examples of the removing method includeetching, cutting, grinding, polishing, blasting, and the like. Thesecond light-reflective member 50 is preferably removed by etching,cutting, grinding, polishing, blasting, or the like, which can flattenthe surface 52 of the second light-reflective member 50 opposite to theother surface thereof facing the first light-reflective member 10.

Step A-3. Singulation of the Light Emitting Device

The first light-reflective member and the second light-reflective memberbetween the adjacent light-emitting elements are cut to separate intoindividual light-emitting devices. Specifically, the firstlight-reflective member 10, the second light-reflective member 50, andthe support member 80 are cut, for example, by a dicer or the like,along dashed lines X1, X2, X3, and X4, each of which extends through thepart between the adjacent light-emitting elements 40, to perform thesingulation (see FIGS. 5A and 5B). Finally, the support member 80 isremoved, so that the light emitting devices is produced (see FIGS. 6Aand 6B). Preferably, the support member 80 is not completely cut at thetime of cutting the first light-reflective member 10, the secondlight-reflective member 50, and the support member 80. That is, as shownin FIG. 6C, preferably, the first reflective member 10 and the secondreflective member 50 are separated by the cutting portions 108, whilethe support member 80 is not cut out. With this arrangement, the supportmember 80 is not separated into a plurality of parts, so that thesupport member 80 can be removed at one time. Note that the supportmember 80 may be removed before cutting, and then the firstlight-reflective member 10 and the second light-reflective member 50 maybe cut. With such cutting, a plurality of light emitting devices, eachhaving one light-emitting element 40, can be manufactured at the sametime. Alternatively, cutting may be performed in such positions as tocontain a plurality of light-emitting elements 40 in one light emittingdevice.

In the above-mentioned first embodiment, the first light-reflectivemember and/or light-transmissive resin 30 are removed through steps 1 to4 to thereby produce the thinned covering member 70, and thethus-obtained covering member 70 is used to perform the steps A-1 toA-3.

However, in the method of manufacturing the light emitting device in thefirst embodiment, after the step 1-3 and the steps A-1 and A-2 areperformed subsequently, the first light-reflective member and/or thelight-transmissive resin 30 may be removed to thin the covering member70. Further, in the method of manufacturing the light emitting device inthe first embodiment, after the step 1-3, and the steps A-1 to A-3 areperformed subsequently, the first light-reflective member and/or thelight-transmissive resin 30 may be removed in each of the light emittingdevices to thin the covering member 70.

Second Embodiment

A method of manufacturing a light emitting device in the secondembodiment will be described below.

The method of manufacturing the light emitting in the second embodimentis substantially the same as that in the first embodiment except thatthe covering member is fabricated in a way different from that of thefirst embodiment.

The fabrication method of the covering member in this embodiment will bedescribed below.

Fabrication of Covering Member

Step 2-1. Preparation of the First Light-Reflective Member

A first light-reflective member 10 with recesses 107 is formed over thesupport member 80 made of a heat-resistant sheet or the like. In thecase where the surface of the first light-reflective member 10 oppositeto the support member 80 is referred to as a first surface 101 while thesurface opposite to the first surface is referred to as a second surface102, the recesses 107 are formed to be opened on the side of the secondsurface 102 (see FIG. 7A).

Step 2-2. Placing of the Light-Transmissive Resin 30 Containing theWavelength-Conversion Material 20

Then, the light-transmissive resin 30 containing thewavelength-conversion material 20 is placed within each through-hole 107(see FIG. 7B). To place the light-transmissive resin 30 containing thewavelength-conversion material 20, any method known in the art may beused. Examples of the known method include printing, potting, etc. Notethat the light-transmissive resin 30 should be in a state of making thewavelength-conversion material 20 movable within the light-transmissiveresin 30. That is, the light-transmissive resin 30 may be in the liquidstate before curing, or in a semi-cured state. The light-transmissiveresin 30 is preferably in the liquid state, since it allows thewavelength-conversion material 20 to easily move therein, compared tothat in the semi-cured state.

Step 2-3. Distributing the Wavelength-Conversion Material 20

The wavelength conversion material 20 is distributed predominantly onthe first surface 101 side (on the bottom surface side of the recess)within the light-transmissive resin 30 due to the spontaneousprecipitation or forced precipitation (see FIG. 7C). Thereafter, thelight-transmissive resin 30 is cured by heating or the like. As aresult, the light-transmissive resin in which the wavelength-conversionmaterial 20 is eccentrically distributed predominantly on the firstsurface 101 side is obtained.

Step 2-4. Removal of the First Light-Reflective Member and theLight-Transmissive Resin

Upper parts located above the dashed line Ct1-Ct1 of FIG. 7C areremoved. That is, the “first light-reflective member on the secondsurface side” and the “light-transmissive resin 30 on the side oppositeto the side where the wavelength-conversion material 20 is distributedpredominantly” are removed. To remove the first light-reflective member10 and the light-transmissive resin 30, any method known in the art maybe used. Examples of the removing method include etching, cutting,grinding, polishing, blasting, and the like. With such removing, thefirst light-reflective member and the light-transmissive resin can bethinned while keeping the light-transmissive resin 30 on the side wherethe wavelength-conversion material 20 is predominantly distributed.

When removing the first light-reflective member and thelight-transmissive resin by the etching, cutting, grinding, polishing,blasting, or the like, the “second surface side of firstlight-reflective member 10” and the “side of the light-transmissiveresin 30 opposite to the side where the wavelength-conversion material20 is predominantly distributed” may be roughened. Roughening thesesurfaces can reduce the tackiness thereof, which allows for easyhandling.

Step 2-5. Removal of the First Light-Reflective Member

The support member 80 is removed from the first surface of the firstlight-reflective member 10, and then the support member 80 is bonded tothe second surface of the first light-reflective member 10 (the surfaceopposite to the first surface) (see FIG. 7D). At this time, anothersupport member 80 may be bonded to the second surface of the firstlight-reflective member 10, followed by removing the previous supportmember 80 from the first surface. Then, a portion of the “firstlight-reflective member on the first surface side” that is located abovethe dashed line Ct2-Ct2 of FIG. 7D is removed (see FIG. 7E). To removethe first light-reflective member 10, any method known in the art may beused. Examples of the removal method include etching, cutting, grinding,polishing, blasting, and the like. With such removing, thelight-transmissive resin 30 containing the wavelength-conversionmaterial 20 is also exposed from the first surface 101 side. That is,the thinned covering member 70 can be obtained. Note that either thestep 2-4 or the step 2-5, which are steps of removing, may be performedfirst.

Third Embodiment

A method of manufacturing a light emitting device in a third embodimentdiffers from that in the first embodiment in that:

(1) While the light-transmissive resin 30 is cured in the step 1-3 inthe first embodiment, in the method of manufacturing the light emittingdevice in the third embodiment, in the step 1-3, the light-transmissiveresin 30 is brought into the semi-cured state to be adhesive, andadhesiveness of the light-transmissive resin 30 is kept until thelight-emitting element 40 is fixed.

(2) While the light-emitting element 40 and the light-transmissive resin30 are bonded together via the bonding member in the step A-1 in thefirst embodiment, in the method of manufacturing the light emittingdevice in the third embodiment, in step A-1, the light-emitting element40 and the light-transmissive resin 30 are fixed together using theadhesiveness of the semi-cured light-transmissive resin 30.

The method of manufacturing the light emitting device in the thirdembodiment is the same as that in the first embodiment except for theabove-mentioned (1) and (2).

In the method of manufacturing the light emitting device according tothe third embodiment, the light-emitting element 40 and thelight-transmissive resin 30 are fixed together using the adhesiveness ofthe semi-cured light-transmissive resin 30 based on the method ofmanufacturing the first embodiment.

Also in the method of manufacturing the second embodiment, thelight-emitting element 40 and the light-transmissive resin 30 may befixed together using the adhesiveness of the semi-curedlight-transmissive resin 30.

In the method of manufacturing the light emitting device in the thirdembodiment as mentioned above, preferably, after the step 1-3 and thesteps A-1 and A-2 are performed sequentially, the first light-reflectivemember and/or light-transmissive resin 30 are preferably removed to thinthe covering member 70.

With the methods of manufacturing the light emitting device according tothe first to the third embodiments, the covering member 70 can bethinned by grinding, polishing, or the like, which allows for easilymanufacturing of the thinned light emitting device.

In the methods of manufacturing a light emitting device according to thefirst to the third embodiments as mentioned above, after thewavelength-conversion material 20 is distributed predominantly on onesurface side of the light-transmissive resin 30, a region of thelight-transmissive resin 30 where wavelength-conversion material 20 isnot predominantly distributed is removed to thin the covering member 70.

With this arrangement, the thinned covering member 70 with smallvariations in content of the wavelength-conversion material 20 can beformed, so that variations in color tone of the light emitting devicecan be reduced. More specifically, if the wavelength-conversion material20 is predominantly distributed without removing the region where thewavelength-conversion material 20 that is not predominantly distributedin order to fabricate a thin covering member including thewavelength-conversion material, a small amount of light-transmissiveresin may be possibly applied into the through-holes or openings of thethin first light-reflective member.

However, if an amount of resin applied is small, variance in the amountof resin applied tends to increase, which may cause large variance inthe content of the wavelength-conversion material in thelight-transmissive resin. After the wavelength-conversion material 20 ispredominantly distributed on one surface side of the light-transmissiveresin 30, the region of the light-transmissive resin 30 where thewavelength-conversion material 20 is not predominantly distributed isremoved to thin the covering member 70. In this case, the amount thelight-transmissive resin that is applied into the through-holes oropenings of the first light-reflective member can be relatively large.Accordingly, the thinned covering member 70 with small variance in thecontent of the wavelength-conversion material 20 can be formed.

In the methods of manufacturing a light emitting device according to thefirst to the third embodiments as mentioned above, after thewavelength-conversion material 20 is predominantly distributed on onesurface side of the light-transmissive resin 30, a region of thelight-transmissive resin 30 where wavelength-conversion material 20 isnot predominantly distributed is removed to thin the covering member 70.With these methods, the thinned covering member 70 can be formed withhigh processing accuracy.

That is, if the thin first light-reflective member having thethrough-holes or openings is used and the light-transmissive resin 30 ischarged into the through-holes or openings to fabricate the thincovering member, it may be difficult to fabricate the covering memberwith the high processing accuracy due to, for example, the deformationof the thin first light-reflective member not charged with thelight-transmissive resin 30 in the through-holes or openings, or thedeformation of the thin first light-reflective member that would occurwhen the light-transmissive resin 30 is charged and cured in thethrough-holes or openings, which may occur in the manufacturing process.

However, in methods of manufacturing the light emitting device accordingto the first to the third embodiments, with use of the relatively-thickfirst light-reflective member that is easy to handle in themanufacturing procedure, the covering member in which thelight-transmissive resin 30 has been charged in the through-holes oropenings of the first light-reflective member and cured to produce thecoating member with a high strength, and then the high-strength coveringmember is thinned by polishing, grinding, or the like. With this method,the thin covering member can be fabricated with the high processingaccuracy to manufacture the light emitting device.

Therefore, with the methods of manufacturing the light emitting deviceaccording to the first to the third embodiments, the light emittingdevice can be manufactured with the high processing accuracy.

As mentioned above, with the methods of manufacturing the light emittingdevice according the first to third embodiments, the thin coveringmember can be manufactured with the high processing accuracy tomanufacture the light emitting device. Accordingly, the light emittingdevice with small variance in light distribution properties can bemanufactured.

That is, in case of fabricating the thin covering member without beingthinned by polishing, grinding, or the like with use of the thin firstlight-reflective member having the through-holes or openings into whichthe light-transmissive resin is charged, variance in the shape of thelight-transmissive resin obtained after curing tends to become large,which might lead to large variance in light distribution properties.

For example, in the case where the light-transmissive resin is appliedinto the through-holes or openings in the first light-reflective memberby potting or the like and is then cured, a phenomenon of the so-calledshrinkage may occur, so that the surface of the resin may be recessed.Such recessed surface may lead to degradation in the light extractionefficiency of the light emitting device. Variance of the shape of thesurface (e.g., degree of recess of the recessed surface) due to variancein the degree of shrinkage may cause variance in light distributionproperties.

However, in the above-mentioned methods of manufacturing the lightemitting device in the first to the third embodiments, the region of thelight-transmissive resin 30 where the wavelength-conversion material 20is not predominantly distributed is removed to thin the covering member70, so that the recessed part formed on the surface due to the shrinkagecan be removed and flattened, so that variance in the shape of thesurface can be small.

Therefore, the light emitting device with high light extractionefficiency and small variance in light distribution properties can bemanufactured.

Fourth Embodiment

A light emitting device 1000 according to a fourth embodiment is oneexample of the light emitting device fabricated by the methods ofmanufacturing the light emitting device of the first to the thirdembodiments. The light emitting device 1000 according to the fourthembodiment includes: the covering member including the firstlight-reflective member 10 with through-holes, and thelight-transmissive resin 30, which is disposed in the through-holes ofthe first light-reflective member 10 and contains wavelength-conversionmaterials 20; the light-emitting element 40 facing thelight-transmissive resin 30; and the second light-reflective member 50covering lateral surfaces of the light-emitting element 40 and facingthe first light-reflective member around the light-emitting element 40.The wavelength-conversion material 20 is predominantly distributed onthe side of the surface of the light-transmissive resin 30 facing thelight-emitting element 40. That is, the surface of thelight-transmissive resin 30 where the wavelength-conversion material 20is predominantly distributed faces a light extraction surface 401 of thelight-emitting element 40. In the case of mounting the light-emittingelement 40 on a base, the light extraction surface 401 of thelight-emitting element 40 is referred to as a surface opposite to thesurface of the light-emitting element 40 facing the base. In otherwords, in the case of mounting the light-emitting element 40 in aface-down manner, the light extraction surface refers to a surfaceopposite to the surface of the light-emitting element on which theelectrodes are disposed. In the case of mounting the light-emittingelement 40 in a face-up manner, the light extraction surface is referredto as the surface of the light-emitting element on which the electrodesare disposed. Furthermore, the surface having the electrodes thereon isreferred to as an electrode formation surface.

FIG. 8B is a cross-sectional view taken along the line A-A of FIG. 8A.As shown in FIG. 8B, the light-emitting element 40 includes alight-transmissive substrate 41 and a semiconductor laminated body 42formed on the lower surface side of the light-transmissive substrate 41.The light-emitting element 40 has the light extraction surface 401(upper surface) on the light-transmissive substrate 41 side and theelectrode formation surface 402 (lower surface) opposite to the lightextraction surface. Further, the light-emitting element 40 includes apair of electrodes 43 and 44 on the electrode formation surface 402(lower surface). Each of the two electrodes 43 and 44 forming the pairof electrodes can have any shape. Note that the term “electrodeformation surface” of the light-emitting element 40 as used in thepresent specification indicates the surface of the light-emittingelement 40 that does not include the electrodes 43 and 44. In thepresent embodiment, the electrode formation surface 402 corresponds tothe lower surface of the semiconductor layered body 42.

The through-hole formed in the first light-reflective member 10 may havean appropriate shape, examples of which include: a shape including acurved line such as a circle, an ellipse, a semicircle, and asemi-ellipse; a polygonal shape such as a triangle and quadrangle; andan irregular shape such as a T shape and an L shape. In order to enhancethe extraction efficiency of light emitted from the light-emittingelement 40, the light-transmissive resin 30 disposed in eachthrough-hole preferably has a width larger than the region enclosed bythe periphery of the light-emitting element 40. With the width of thelight-transmissive resin 30 larger than the region enclosed by theperiphery of the light-emitting element 40, the amount of lightreflected by the first light-reflective member 10 and returning to thelight-emitting element 40 can be reduced. On the other hand, in order toimprove the visibility of the light emitting device, the width of thelight-transmissive resin 30 is preferably smaller than the regionenclosed by the periphery of the light-emitting element 40. With thewidth of the light-transmissive resin 30 smaller than the regionenclosed by the periphery of the light-emitting element 40, the areafrom which the light is extracted can be decreased.

The second light-reflective member 50 covers the lateral surfaces of thelight-emitting element 40 and the first light-reflective member 10. Thesecond light-reflective member 50 may cover the electrode formationsurface 402 of the light-emitting element 40 so as to expose portions ofthe electrodes 43 and 44.

In the light emitting device 1000, the wavelength-conversion material 20is distributed predominantly on the first surface 101 side in thelight-transmissive resin 30. With this arrangement, a decrease in thecontent of the wavelength-conversion material 20 contained in thelight-transmissive resin 30 can be reduced, even in the case whereportions of the first light-reflective member 10 and thelight-transmissive resin 30 on the side where the wavelength-conversionmaterial 20 is not predominantly distributed (on the second surface 102side) are removed. That is, the light emitting device can be thinnedwithout significantly changing the content of the wavelength-conversionmaterial 20 in the light-transmissive resin 30. Further, even if thethickness of the light-transmissive resin 30 is slightly uneven, thecontent of the wavelength-conversion material 20 in thelight-transmissive resin 30 does not change largely. Preferably, thesurface (upper surface) of the light-transmissive resin 30 on the sidewhere the wavelength-conversion material 20 is not predominantlydistributed (on the second surface 102 side) is located on thesubstantially same plane (or is flush with) as the second surface 102which is the upper surface of the first light-reflective member 10, nostepped portion presents between both surfaces, and both surfaces areflat. In this way, the light emitting device can be further thinned.Note that the expression “flush and no stepped portion” as used hereinmeans that one of both surfaces is not intentionally processed toprotrude from the other. Specifically, irregularities with a height ofabout 50 μm or smaller and preferably about 30 μm or smaller is regardedas the flush part or the part without any stepped portion.

In the light emitting device 1000, the surface of the light-transmissiveresin 30 where the wavelength-conversion material 20 is predominantlydistributed faces a light extraction surface 401 of the light-emittingelement 40. That is, the surface of the light-transmissive resin 30constituting a part of the upper surface of the light emitting device1000 and being exposed to the outside air is the surface of thelight-transmissive resin 30 where the wavelength-conversion material 20is not predominantly distributed. Thus, substantially nowavelength-conversion material 20 exists near the surface of thelight-transmissive resin 30 exposed to the outside air. With thisarrangement, for example, even though the wavelength-conversion material20 susceptible to moisture is used, the light-transmissive resin 30 canserve as a protective layer, which can suppress the degradation of thewavelength-conversion material 20, so that good color tone can be kept.Examples of the wavelength-conversion material 20 susceptible tomoisture include a fluoride-based phosphor, a sulfide-based phosphor, achloride-based phosphor, a silicate-based phosphor, and aphosphate-based phosphor. In particular, although K2SiF6:Mn as thefluoride-based phosphor is suitable for use as a red phosphor,conventionally, application of K2SiF6:Mn is limited due to itssusceptibility to moisture.

However, with the light emitting device according to the fourthembodiment, change of color tone can be reduced even in the case ofcontaining K2SiF6:Mn for the fluoride-based phosphor. When the lightemitted from the light-emitting element 40 strikes thewavelength-conversion material 20, it is refracted and scattered by thewavelength-conversion material 20. The upper surface of the lightemitting device 1000 is formed of the surface where thewavelength-conversion material 20 is not predominantly distributed inthe light-transmissive resin 30. With this arrangement, the portion atwhich the light is mainly scattered is located in the lower side of thelight emitted device, compared to a light emitting device in which thewavelength-conversion material 20 is dispersedly distributed in thelight-transmissive resin 30. In this way, in the case where the uppersurface of the light emitting device is formed of the surface where thewavelength-conversion material 20 in the light-transmissive resin 30 isnot eccentrically located, the light emitting device can have goodvisibility.

Fifth Embodiment

As shown in FIG. 9, a light emitting device 2000 in a fifth embodimentdiffers from the light emitting device 1000 in the fourth embodiment inthat the surface of the light-transmissive resin 30 opposite to thesurface thereof where the wavelength-conversion material 20 ispredominantly distributed faces the light extraction surface 401 of thelight-emitting element 40. The fifth embodiment is the same as thefourth embodiment except for the above-mentioned point.

Preferably, on the side where the wavelength-conversion material 20 isnot predominantly distributed (the second surface 102 side), the firstlight-reflective member 10 and the light-transmissive resin 30 are flushwith each other, no stepped portion presents between both surfaces, andboth surfaces are flat. In this way, the light emitting device can befurther thinned. Note that the expression “flush and no stepped portion”as used herein means, similarly to the fourth embodiment, that one ofboth surfaces is not intentionally processed to protrude from the other.Specifically, irregularities with a height of about 50 μm or smaller andpreferably about 30 μm or smaller are allowable.

In the fifth embodiment, the part of the light-transmissive resin 30 atwhich wavelength-conversion material 20 is not predominantly distributedis disposed between the light-emitting element 40 and the side of theresin where the wavelength-conversion material 20 is predominantlydistributed. With this arrangement, the distance between thelight-emitting element 40 and the wavelength-conversion material 20 canbe made longer, compared to the case in which the wavelength-conversionmaterial 20 is dispersed in the light-transmissive resin 30.Accordingly, the heat generated from the light-emitting element 40 canbe suppressed from being transferred to the wavelength-conversionmaterial 20 even in the use of, for example, the wavelength-conversionmaterial 20 susceptible to heat or having large variations in itsexcitation efficiency depending on its temperature. Therefore, goodcolor tone can be maintained. Examples of the wavelength-conversionmaterial 20 susceptible to the heat or having large variations in itsexcitation efficiency depending on its temperature include a quantum dotphosphor, a chloro-silicate phosphor, and a β-sialon phosphor.

Sixth Embodiment

A light emitting device 3000 in a sixth embodiment shown in FIG. 10differs from the light emitting device 1000 according to the fourthembodiment in that the upper surface of the light emitting device 3000is rougher than the lower surface of the light emitting device 3000. Inother words, the lower surface of the light emitting device 3000 isflatter than the upper surface of the light emitting device 3000. Thesixth embodiment is the same as the fourth embodiment except for theabove-mentioned point.

The upper surface of the light emitting device 3000 includes the secondsurface of the first light-reflective member 10 and a surface oppositeto the surface of the light-transmissive resin 30 toward which thewavelength-conversion material is predominantly distributed. The lowersurface of the light emitting device 3000 includes a surface 52 oppositeto the surface of the second light-reflective member 50 facing the firstlight-reflective member 10, and exposed surfaces 431 and 441 that aresurfaces of the electrodes of the light-emitting element exposed fromthe second light-reflective member. The second surface 102 of the firstlight-reflective member 10 that constitute a part of the upper surfaceof the light emitting device 3000 is preferably rougher than each of theexposed surfaces 431 and 441. Alternatively, in the light-transmissiveresin 30 which forms a part of the upper surface of the light emittingdevice 300, one surface of the light-transmissive resin 30 opposite tothe other surface thereof where the wavelength-conversion material ispredominantly distributed is preferably rougher than the exposedsurfaces 431 and 441.

Roughening the upper surface of the light emitting device 3000 canreduce tackiness, which makes it easier to handle the light emittingdevice 3000 at the time of mounting it. Note that the exposed surfaces431 and 441 form a part of the lower surface of the light emittingdevice 3000 and serve as the surfaces of the electrodes of thelight-emitting element exposed from the second light-reflective member,and hence these surfaces 431 and 441 are preferably substantially flat.The exposed surfaces 431 and 441 preferably have a higher specularreflectivity than that of the lower surface of the secondlight-reflective member (surfaces around the exposed surfaces 431 and441). With this structure, a difference in contrast between the exposedsurfaces and the second light-reflective member 50 can be increased.Large contrast difference around the exposed surfaces 431 and 441 allowsfor easy recognition of the electrodes 43 and 44. The second surface 102and the surface of the light-transmissive resin 30 opposite to thesurface thereof where the wavelength-conversion material ispredominantly distributed may have an appropriate arithmetic averageroughness Ra. However, to easily handle the light emitting device, thearithmetic average roughness Ra of the second surface is preferably in arange of 0.05 to 10 μm, and more preferably in a range of 0.07 to 5 μm.The surface of the light-transmissive resin 30 opposite to the surfacethereof where the wavelength-conversion material is predominantlydistributed may have an appropriate arithmetic average roughness Ra.However, in order to easily handle the light emitting device, thearithmetic average roughness Ra of this surface is preferably in a rangeof 0.05 to 10 μm, and more preferably in a range of 0.07 to 5 μm. Eachof the exposed surfaces 431 and 441 may have an appropriate arithmeticaverage roughness Ra. However, in order to easily recognize the exposedsurfaces, the arithmetic average roughness Ra arithmetic averageroughness Ra is preferably 0.1 μm or less, more preferably 0.05 μm orless, and much more preferably 0.025 μm or less.

Ra can be measured in conformity with the measurement method of thesurface roughness of JIS0601-1976. More specifically, Ra can berepresented by the formula in [Equation 1], in which a part with ameasurement length L is extracted from a roughness curve in thedirection of its central line, the central line of the extracted part isrepresented as the X axis, the axial magnification direction isrepresented as the Y axis, and the roughness curve represented asy=f(x).

Ra=1/L×∫ ₀ ^(L) |f(x)|dx

Value of Ra is represented in unit of micrometer. The Ra can be measuredby using a contact surface roughness gauge or a laser microscope. Notethat the arithmetic average roughness Ra in the present specification ismeasured by using SURFCOM480A-12 manufactured by TOKYO SEIMITSU Co.,Ltd.

Also in the light emitting device 2000, the first surface 101 of thefirst light-reflective member 10, which serves as the upper surface ofthe light emitting device 2000, and the surface of thelight-transmissive resin 30 where the wavelength-conversion material 20is predominantly distributed are preferably rougher than the exposedsurfaces 431 and 441 forming a part of the lower surface of the lightemitting device 2000. With this structure, similarly to the lightemitting device 3000, the light emitting device 2000 can be easilyhandled.

Seventh Embodiment

A light emitting device 4000 according to a seventh embodiment shown inFIG. 11 differs from the light emitting device 1000 according to thefourth embodiment in that the light-emitting element 40 and thelight-transmissive resin 30 are bonded together via the bonding member60. The seventh embodiment is the same as the fourth embodiment exceptfor the above-mentioned point.

It is preferable to arrange the bonding member 60, which islight-transmissive, between the light-emitting element 40 and thelight-transmissive resin 30 because using the bonding member 60 allowsthe light-emitting element 40 and the light-transmissive resin 30 to beeasily bonded together. Also, arrangement of the bonding member 60between the light-emitting element 40 and the light-transmissive resin30 causes the refraction or reflection of light at the interface betweenthe bonding member 60 and the light-transmissive resin 30. Accordingly,the color unevenness and the luminance unevenness can be reduced. Therefractive index of the bonding member 60 is preferably closer to thatof the light extraction surface 401 of the light-emitting element 40rather than that of the light-transmissive resin 30, which allowed theextraction efficiency of light from the light-emitting element 40 to beenhanced.

In the case where the bonding member 60 is formed up to the sidesurfaces of the light-emitting element 40, the light emitted from theside surfaces of the light-emitting element 40 can be extracted from thelight emitting device 4000 through the bonding member 60, which canenhance the light extraction efficiency.

In the case where a width of the light-transmissive resin 30 is largerthan the region defined by the outer edge of the light-emitting element40, the bonding member 60 is preferably bonded with thelight-transmissive resin 30 so that the area of the bonding member 60that contacts the light extraction surface 401 of the light-emittingelement 40 is larger than the area of the light extraction surface 401of the light-emitting element 40. With this arrangement, light emittedfrom the light-emitting element 40 is introduced to thelight-transmissive resin 30 through the region at which the bondingmember 60 and the light-transmissive resin 30 is bonded, the area ofwhich is larger than the area of the light extraction surface 401, sothat color unevenness and luminance unevenness can be reduced. Thebonding member 60 more preferably covers the whole surface of thelight-transmissive resin 30 facing the light-emitting element 40. Inthis way, light emitted from the light-emitting element 40 can beintroduced into the whole surface of the light-transmissive resin 30facing the light-emitting element 40, so that the color unevenness andthe luminance unevenness can be further reduced.

Note that the above-mentioned effects can be obtained even with thearrangement in which the surface of the light-transmissive resin 30opposite to the surface thereof where the wavelength-conversion material20 is predominantly distributed faces the light extraction surface 401of the light-emitting element 40, like the light emitting device 2000 ofthe fifth embodiment.

Eighth Embodiment

A light emitting device 5000 according to an eighth embodiment shown inFIGS. 12, 13A, 13B, and 13C differs from the light emitting device 1000according to the fourth embodiment in that the protrusions 103 arearranged on the sidewall of the through-hole of the firstlight-reflective member 10. The eighth embodiment is the same as thefourth embodiment except for the above-mentioned point.

With the protrusions 103 on the sidewall of the through-hole, lightemitted from the light-emitting element 40 can be reflected by theprotrusions 103, and a large amount of light can be struck on thewavelength-conversion material 20, which can improve the colorunevenness. The location of each protrusion 103 is not specificallylimited. Similarly to the light emitting device 5000 shown in FIG. 12,in the case where the upper surface of the light emitting device isformed of the second surface 102 of the first light-reflective member10, each protrusion 103 is preferably located closer to the secondsurface 102 rather than to the first surface 101 of the firstlight-reflective member 10. With this arrangement, light reflected bythe protrusion 103 is more likely to be struck on thewavelength-conversion material 20, which can improve color unevenness.The protrusion 103 is preferably formed in the position closer to theupper surface of the light emitting device rather than the lightextraction surface of the light-emitting element. This can improve thevisibility of the light emitting device. For improving visibility,forming the protrusion 103 can use a larger amount of thelight-transmissive resin 30 compared to decreasing the size of thethrough-hole, so that forming the protrusion 103 can further reduce thecolor unevenness. Note that the term “location of the protrusion 103” asused in the present specification refers to a location of a tip end ofthe protrusion 103.

The presence of the protrusion 103 on the sidewall of the through-holecan increase the adhesive area between the first light-reflective member10 and the light-transmissive resin 30 containing thewavelength-conversion material 20, which can enhance the adhesive forcetherebetween. As shown in FIG. 13A, the protrusion 103 may be inclinedand protruded toward the first surface 101 side. In other words, theprotrusion 103 may be inclined toward the first surface 101 side. Withinclination of the protrusion 103, the adhesive area can be increased,so that adhesive force can be enhanced. As shown in FIG. 13B, theprotrusion 103 may be inclined and protruded toward the second surface102 side. In other words, the protrusion 103 may be inclined toward thesecond surface 102 side. Even with this arrangement, the adhesive areabetween the first light-reflective member 10 and the light-transmissiveresin 30 can be increased to enhance the adhesive force. Furthermore,reflection pf light emitted from the light-emitting element 40 by theprotrusion 103 allows the light more likely to be directed toward theupper surface of the light emitting device, which can improve the lightextraction efficiency. As shown in FIG. 13C, the light-emitting element40 and the light-transmissive resin 30 may be bonded together via thebonding member 60. With this arrangement, refraction or reflection oflight occurs at the interface between the bonding member 60 and thelight-transmissive resin 30, and also light reflection by theprotrusions 103 occurs, so that color unevenness can be furtherimproved.

Ninth Embodiment

A light emitting device 6000 according to the present embodiment shownin FIGS. 14A and 14B differs from the light emitting device 1000according to the fourth embodiment in that light diffusion material iscontained in the light-transmissive resin 30. FIG. 14A shows that afirst light diffusion material 31 is contained in the light-transmissiveresin 30, whereas FIG. 14B shows that the first light diffusion material31 and a second light diffusion material 32 are contained in thelight-transmissive resin 30. The ninth embodiment is the same as thefourth embodiment except for the above-mentioned point.

As illustrated in FIG. 14A, the light-transmissive resin 30 preferablycontains the first light diffusion material 31, which can adjust itsrefractive index. The refractive index of the first light diffusionmaterial at 25° C. (normal temperature) is preferably higher than thatof the light-transmissive resin at 25° C. (normal temperature). Thus, adifference in the refractive index between the light-transmissive resin30 and the first light diffusion material 31 at a high temperature (100°C.) is larger than that at the normal temperature (25° C.). This isbecause the light-transmissive resin 30 reduces its refractive index dueto the thermal expansion when its temperature increases due to drivingof the light emitting device or the like. Typically, the first lightdiffusion material 31 does not decrease its refractive index as much asthe light-transmissive resin 30 even when its temperature increases.Further, the wavelength-conversion efficiency of thewavelength-conversion material 20 is degraded when its temperatureincreases. At a high temperature (100° C.), the difference in therefractive index between the light-transmissive resin 30 and the firstlight diffusion material 31 increases, which increase light reflectivityof the first light diffusion material 31 with respect to light emittedfrom the light-emitting element 40, so that an optical path length inwhich light emitted from the light-emitting element 40 passes throughthe light-transmissive resin 30 can be increased. Thus, the amount oflight striking the wavelength-conversion material 20 increases, so thatcolor unevenness can be reduced even when the fluorescent-emissionefficiency of the wavelength-conversion material 20 is reduced.

Preferably, the first light diffusion material 31 is uniformly dispersedin the light-transmissive resin 30. The uniform dispersion of the firstlight diffusion material 31 can reduce the color unevenness in thelight-transmissive resin 30. Preferably, the first light diffusionmaterial 31 is dispersed in the light-transmissive resin 30, and thewavelength-conversion material 20 is distributed predominantly betweenthe first light diffusion material 31 and the light extraction surface401 of the light-emitting element 40. That is, the first light diffusionmaterial is preferably contained in a region of the light-transmissiveresin other than the region where the wavelength-conversion material isnot predominantly distributed. With this arrangement, the light emittedfrom the light-emitting element 40 is more likely to be reflected by thefirst light diffusion material 31 and then to strike thewavelength-conversion material 20, which can further reduce the colorunevenness in the light-transmissive resin 30. Thus, although thewavelength-conversion material 20 is unevenly distributed, a materialfor the first light diffusion material 31 is preferably selected frommaterials that is less likely to precipitate in the non-cured orsemi-cured light-transmissive resin 30, compared to thewavelength-conversion material 20 in that, and that can maintain to beuniformly dispersed. Specifically, in the case of selecting phosphorparticles having an average grain size of 5 μm to 20 μm for thewavelength-conversion material 20, for example, powder material havingan average grain size of 0.1 μm to 3 μm, preferably, 0.2 μm to 1 μm canbe used for the first light diffusion material 31. Furthermore, thefirst light diffusion material 31 is contained to enable adjustment ofthe viscosity of the light-transmissive resin 30. This arrangement ispreferable because it allows the light-transmissive resin 30 to beformed easily.

As shown in FIG. 14B, the first light diffusion material 31 and thesecond light diffusion material 32 may be contained in thelight-transmissive resin 30. At this time, preferably, the refractiveindex of the first light diffusion material at 25° C. (normaltemperature) is higher than that of the light-transmissive resin at 25°C. (normal temperature), whereas the refractive index of the secondlight diffusion material at 100° C. (high temperature) is lower thanthat of the light-transmissive resin 30 at 100° C. (high temperature).With this arrangement, at a high temperature (100° C.), compared withthe normal temperature (25° C.), the difference between the refractiveindex of the light-transmissive resin 30 and that of the first lightdiffusion material 31 is increased, whereas the difference between therefractive index of the light-transmissive resin 30 and that of thesecond light diffusion material 32 is reduced. Accordingly, thedifference between the refractive index of the light-transmissive resin30 and that of the first light diffusion material 31 and the differencebetween the refractive index of the light-transmissive resin 30 and thatof the second light diffusion material 32 are complementary to eachother, which can further reduce the color unevenness due to the changein temperature. The first light diffusion material 31 and the secondlight diffusion material 32 are preferably dispersed in thelight-transmissive resin 30. The dispersion of the first and secondlight diffusion materials 31 and 32 can reduce the color unevenness inthe light-transmissive resin 30. Alternatively, two or more kinds oflight diffusion materials may be contained in the light-transmissiveresin 30.

Note that unless otherwise specified, the refractive index in thepresent specification is a value at a peak wavelength of the light fromthe light-emitting element. Further, unless otherwise specified, thedifference in the refractive index is represented by the absolute value.The refractive index can be measured, for example, by an Abbrefractometer. In the case where the refractive index of a member cannotbe measured with the Abb refractometer due to the size of the member tobe measured or the like, the member to be measured is specified, and arefractive index of a material similar to the specified member ismeasured. Then, the refractive index of the specified component can bededuced from the measurement result of the similar material.

Tenth Embodiment

A light emitting device 7000 according to a tenth embodiment as shown inFIG. 15A differs from the light emitting device 1000 according to thefourth embodiment in that an upper surface of the light emitting device7000 is rougher than a lower surface of the light emitting device 7000,that the light-emitting element 40 and the light-transmissive resin 30are bonded together via the bonding member 60, that sidewalls of athrough-hole of the first light-reflective member 10 have theprotrusions 103, and that the light diffusion material is contained inthe light-transmissive resin 30. The tenth embodiment is the same as thefourth embodiment except for the above-mentioned point.

The upper surface of the light-transmissive resin 30 forming the uppersurface of the light emitting device 7000 is roughened. With thisarrangement, light emitted from the light-emitting element 40 is morelikely to be reflected by the upper surface of the light-transmissiveresin 30. Accordingly, color unevenness can be reduced in thelight-transmissive resin 30. The light-emitting element 40 and thelight-transmissive resin 30 may be bonded together via the bondingmember 60. Part of the light emitted from the light-emitting element 40is refracted or reflected via the bonding member 60 at the interfacebetween the bonding member 60 and the light-transmissive resin 30, sothat color unevenness can be reduced. The protrusions 103 are disposedat the sidewalls of the through-hole in the first light-reflectivemember 10. Thus, a portion of light emitted from the light-emittingelement 40 is reflected by the protrusion 103, which can further reducecolor unevenness. The light diffusion material (first light diffusionmaterial 31, second light diffusion material 32) is contained in thelight-transmissive resin 30. With this configuration, a portion of lightemitted from the light-emitting element 40 is reflected or reflected bythe light diffusion material, which can reduce color unevenness. Withthis arrangement, the optical path length in which light emitted fromthe light-emitting element 40 propagates in the light-transmissive resin30 can be increased, so that color unevenness can be reduced.

A light emitting device 7000 according to an embodiment shown in FIG.15B is a modified example of FIG. 15A, and differs from the structure ofFIG. 15A in that the surface of the light-transmissive resin 30 oppositeto the surface thereof where the wavelength-conversion material 20 ispredominantly distributed is disposed so as to face the light extractionsurface 401 of the light-emitting element 40. The structure shown inFIG. 15B is substantially the same as that shown in FIG. 15A except forthe points mentioned above. Even with this arrangement, the optical pathlength in which light emitted from the light-emitting element 40propagates in the light-transmissive resin 30 can be increased, so thatcolor unevenness can be reduced.

Materials and the like for each components of the light-emitting devicesin the fourth to tenth embodiments will be described below.

Light-Emitting Element 40

For the light-emitting element 40, a semiconductor light-emittingelement such as a light-emitting diode can be used. The semiconductorlight-emitting element can include the light-transmissive substrate 41,and the semiconductor laminated body 42 formed thereon.

Light-Transmissive Substrate 41

Examples of materials for the light-transmissive substrate 41 of thelight-emitting element 40 include, light-transmissive insulatingmaterials such as sapphire (Al2O3) and spinel (MgAl2O4), semiconductormaterials that allow the light from the semiconductor layered body 42 topass therethrough (e.g., nitride-based semiconductor material).

Semiconductor Layered Body 42

The semiconductor layered body 42 includes a plurality of semiconductorlayers. One example of the semiconductor laminated body 42 include threesemiconductor layers, namely, a first conductive-type semiconductorlayer (e.g., n-type semiconductor layer), a light-emission layer (activelayer), and a second conductive-type semiconductor layer (e.g., p-typesemiconductor layer). The semiconductor layers can be formed ofsemiconductor material, such as a III-V group compound semiconductor anda II-VI group compound semiconductor. Specifically, examples of thesemiconductor material include nitride-based semiconductor materialssuch as InXAlYGal-X—YN (0≦X, 0≦Y, X+Y≦1) (e.g., InN, AlN, GaN, InGaN,AlGaN, InGaAlN, etc.)

Electrodes 43 and 44

Electrodes 43 and 44 of the light-emitting element 40 can be formed ofgood electrical conductors. Examples of suitable material for theelectrodes include metal, such as Cu.

First Light-Reflective Member 10

The first light-reflective member 10 can be any member having areflectivity of 60% or more, and preferably 70% or more with respect tolight from the light-emitting element. With this member, light reachedthe first light-reflective member can be reflected to be directed towardthe outside of the light-transmissive resin, which can enhance the lightextraction efficiency of the light emitting device.

Examples of material for the first light-reflective member include metaland light-reflective materials (e.g., titanium oxide, silicon dioxide,titanium dioxide, zirconium dioxide, potassium titanate, alumina,aluminum nitride, boron nitride, mullite, niobium oxide, barium sulfate,various kinds of rare-earth oxides (e.g., yttrium oxide, gadoliniumoxide)). The first light-reflective member may be made of a resin, aninorganic material, glass, etc., or a complex thereof that contains thelight-reflective materials. Note that the content of thelight-reflective material in the resin, inorganic material, glass, and acomplex thereof is appropriately selected, but the content of thelight-reflective material is 10 to 95% by weight, preferably 30 to 80%by weight, and more preferably about 40 to 70% by weight, with respectto the weight of the first light-reflective member. Further, preferably,the light-reflective material is dispersed in the resin to form thefirst light-reflective member, which can facilitate processing such asetching, cutting, grinding, polishing, blasting, and the like.

Examples of resin materials that can be used for the firstlight-reflective member include, particularly, thermosetting resins suchas a silicone resin, a modified silicone resin, an epoxy resin, and aphenol resin; and thermoplastic resins such as a polycarbonate resin, anacrylic resin, a methylpentene resin, and a polynorbornene resin. Inparticular, a silicone resin is preferable because of its goodresistance to light and heat.

Examples of inorganic materials that can be used for the firstlight-reflective member include ceramics or low-temperature co-firedceramics such as aluminum oxide, aluminum nitride, zirconium oxide,zirconium nitride, titanium oxide, titanium nitride, zinc oxide, and amixture thereof. The first light-reflective member may be a single-layerfilm or a laminated film using these materials.

Second Light-Reflective Member 50

The second light-reflective member can be formed using a materialsimilar to that of the first light-reflective member. Material for thesecond light-reflective member may be the same as that of the firstlight-reflective member, but may be different from that depending on therequired properties for the second light-reflective member. For example,the content of the light-reflective material in the firstlight-reflective member may differ from that in the secondlight-reflective member. The second light-reflective member covers thelateral surfaces of the light-emitting element, and thus the secondlight-reflective member may be required to have a higher strength thanthe strength of the first light-reflective member. For this reason, inthe case of forming the first and second light-reflective members fromresin containing the light-reflective material, the content of thelight-reflective material in the second light-reflective member may bedecreased compared to that in the first light-reflective member in ordernot to reduce the strength of the second light-reflective member. Withthis structure, the reflectivity of the first light-reflective memberthat is required to have higher reflectiveness can be increased. Thefirst light-reflective member may be required to have enough strength toundergo a process of removing a part thereof. In this case, the contentof the light-reflective material in the first light-reflective membermay be less than that in the second light-reflective member. With thisarrangement, the strength of the first light-reflective member can behigher than that of the second light-reflective member. Note that thefirst and second light-reflective members may be formed of differentmaterials. Specifically, for example, the first light-reflective membermay be formed of metal or light-reflective material, while the secondlight-reflective member may be formed of resin containing thelight-reflective material.

Light-Transmissive Resin 30

The light-transmissive resin is a member disposed on the lightextraction surface side of the light-emitting element to protect thelight-emitting element from exterior environment and to opticallycontrol the light output from the light-emitting element. Examples ifmaterials for the light-transmissive resin can include thermosettingresins such as silicone resin, modified silicone resin, epoxy resin, andphenol resin; and thermoplastic resins such as polycarbonate resin,acrylic resin, methylpentene resin, and polynorbornene resin. Inparticular, silicone resin is preferable because of its good resistanceto light and heat. The light-transmissive resin preferably has a highlight transmissivity. Thus, normally, no additive that reflects,absorbs, or scatters the light is preferably added to thelight-transmissive resin. However, in order to impart desired propertiesto the light-transmissive resin, some additives may be preferably addedto the light-transmissive resin.

Wavelength-Conversion Material 20

For the wavelength-conversion material, for example, phosphor particlesthat can be excited with light emitted from the light-emitting elementcan be used. Examples of the phosphors that can be excited with thelight from a blue light-emitting element or an UV light-emitting elementinclude an yttrium aluminum garnet based phosphor activated with cerium(Ce:YAG), a lutetium aluminum garnet based phosphor activated withcerium (Ce:LAG), a nitrogen-containing calcium aluminosilicate basedphosphor activated with europium and/or chromium (CaO—Al2O3-SiO2), asilicate based phosphor activated with europium ((Sr, Ba)2 SiO4),nitride based phosphors such as β-SiAlON phosphor, CASN based phosphorand SCASN based phosphor, a fluoride based phosphor such as a KSF basedphosphor, a sulfide based phosphor, a chloride based phosphor, asilicate based phosphor, a phosphate based phosphor, and a quantum-dotphosphor. The KSF based phosphor can be represented by the generalformula below:

A2[M1-aMn4+aF6]  (I)

(where A is at least one kind of cation selected from the groupconsisting of K+, Li+, Na+, Rb+, Cs+, and NH4+; M is at least oneelement selected from the group consisting of the group 4 elements andgroup 14 elements; and “a” satisfies a relationship of 0.01<a<0.20).Also, the phosphor may be a fluoride based phosphor which can berepresented by the general formula (I) where A represents K+ and Mrepresents Si. The combination of these phosphors and the bluelight-emitting element or UV light-emitting element can produce lightemitting devices for emitting various colors (e.g., a white based lightemitting device).

Bonding Member 60

The bonding member can be formed of resin having light-transmissiveness.Examples of materials for the bonding member include, particularly,thermosetting light-transmissive resins such as silicone resin, modifiedsilicone resin, epoxy resin, and phenol resin. The bonding member is incontact with the side surfaces of the light-emitting element and thus issusceptible to heat generated from the light-emitting element duringlighting. The thermosetting resin possesses good heat resistance, andthus is appropriate for the bonding member. The bonding memberpreferably has high light transmissivity. Thus, normally, it ispreferable that no additive that reflects, absorbs, or scatters light isadded to the bonding member. However, in order to impart the desiredproperties to the bonding member, some additives are preferably added tothe bonding member in some cases. For example, various kinds of fillersmay be added to the bonding member in order to adjust the refractiveindex of the bonding member or to adjust the viscosity of the bondingmember before curing.

First Light Diffusion Material 31, Second Light Diffusion Material 32

Examples of the materials for the first and second light diffusionmaterials 31 and 32 include oxides such as SiO2, Al2O3, Al(OH)3, MgCO3,TiO2, ZrO2, ZnO, Nb2O5, MgO, Mg(OH)2, SrO, In2O3, TaO2, HfO, SeO, Y2O3,CaO, Na2O, B2O3, SnO, and ZrSiO4; nitrides such as SiN, AlN, and AlON;and fluorides such as MgF2, CaF2, NaF, LiF, and Na3AlF6. These variouscompounds may be used singly, or alternatively some of these materialsmay be melted and mixed together to be used as glass or the like.Further, alternatively, the first light diffusion material 31 and/or thesecond light diffusion material 32 may be formed as a multilayeredstructure in which a plurality of the materials are stacked.

In particular, with use of the glass, the refractive index of the lightdiffusion material can be appropriately controlled. The grain size ofthe light diffusion material can be appropriately selected from a rangeof 0.01 to 100 μm. The content of each light diffusion material needs tobe adjusted depending on the volume of the coating resin and the grainsize of the light diffusion material, so that cannot be univocallydecided.

While some embodiments according to the present invention have beenexemplified above, it is apparent that the present invention is notlimited to the above-mentioned embodiments and can have any form withoutdeparting from the scope of the present invention.

DESCRIPTION OF REFERENCE NUMERALS

-   -   1000, 2000, 3000, 4000, 5000, 6000, 7000: Light emitting device    -   10: First light-reflective member    -   20: Wavelength-conversion material    -   30: Light-transmissive resin    -   31: First light diffusion material    -   32: Second light diffusion material    -   40: Light-emitting element    -   41: Light-transmissive substrate    -   42: Semiconductor laminated body    -   43, 44: Electrode    -   50: Second light-reflective member    -   60: Bonding member    -   70: Covering member    -   80: Support member    -   90: Upper die    -   91: Holding member    -   92: Lower die    -   101: First surface    -   102: Second surface    -   103: Protrusion    -   106: Through-hole    -   107: Recess    -   108: Cutting portion    -   401: Light extraction surface    -   402: Electrode formation surface

What is claimed is:
 1. A method of manufacturing a covering member, themethod comprising: providing a first light-reflective member having athrough-hole, the through-hole having first and second openings;arranging a light-transmissive resin containing a wavelength-conversionmaterial within the through-hole; distributing the wavelength-conversionmaterial predominantly on a side of the first opening of thethrough-hole within the light-transmissive resin; and after thedistributing of the wavelength-conversion material, removing a portionof the light-transmissive resin from a side of the second opening of thethrough-hole.
 2. The method of manufacturing a covering member accordingto claim 1, wherein a portion of the first light-reflective member isremoved together with the portion of the light-transmissive resin in thestep of removing the portion of the light-transmissive resin.
 3. Themethod of manufacturing a covering member according to claim 1, whereinthe through-hole is formed by punching in the step of providing thefirst light-reflective member.
 4. The method of manufacturing a coveringmember according to claim 1, wherein a plurality of the through-holesare formed in the step of providing the first light-reflective member.5. A method of manufacturing a light emitting device, the methodcomprising: providing a light-emitting element having a light extractionsurface; bonding the light extraction surface of the light-emittingelement to the light-transmissive resin of the covering membermanufactured by the method according to claim 1; forming a secondlight-reflective member so as to be bonded to the first light-reflectivemember around the light-emitting element and cover a lateral surface ofthe light-emitting element.
 6. The method of manufacturing a lightemitting device according to claim 5 further comprising removing a partof the second light-reflective member to expose electrode of thelight-emitting element after the step of forming the secondlight-reflective member.
 7. A method of manufacturing a plurality oflight emitting devices, the method comprising: providing a plurality oflight-emitting elements, each having a light extraction surface, bondingthe light-transmissive resin of each of the through-holes or recesses ofthe covering member manufactured by the method according to claim 4 tothe light extraction surface of each of light-emitting elements; forminga second light-reflective member so as to be bonded to the firstlight-reflective member around each of the light-emitting elements andto cover a lateral surface of each of the light-emitting elements, afterforming of the second light-reflective member, cutting the firstlight-reflective member and the second light-reflective member betweenadjacent light-emitting elements to form a plurality of separate lightemitting devices.
 8. The method of manufacturing a plurality of lightemitting devices according to claim 7, wherein each of thelight-emitting elements is bonded to the light-transmissive resin via abonding member.
 9. The method of manufacturing a plurality of lightemitting devices according to claim 7 further comprising, after formingthe second light-reflective member, removing a portion of the secondlight-reflective member to expose an electrode of each of thelight-emitting elements.
 10. A light emitting device comprising: acovering member including a first light-reflective member having athrough-hole, and a light-transmissive resin disposed in thethrough-hole; a light-emitting element arranged to face thelight-transmissive resin; and a second light-reflective member arrangedto face the first light-reflective member around the light-emittingelement, the second light-reflective member covering a lateral surfaceof the light-emitting element, wherein the light-transmissive resincontains a wavelength-conversion material distributed predominantly oneither (i) a side of a lower surface of the light-transmissive resinfacing the light-emitting element, or (ii) a side of an upper surface ofthe light-transmissive resin apart from the light-emitting element. 11.The light emitting device according to claim 10, wherein thewavelength-conversion material is distributed predominantly on the sideof the lower surface.
 12. The light emitting device according to claim10, wherein the upper surface of the light-transmissive resin and theupper surface of the first light-reflective member resin are located insubstantially the same plane.
 13. The light emitting device according toclaim 10, wherein the upper surface of the light-transmissive resin is arough surface.
 14. The light emitting device according to claim 10,wherein the light-emitting element includes an electrode exposed fromthe second light-reflective member, and a surface of the electrode thatis exposed from the second light-reflective member has a specularreflectivity higher than a specular reflectivity of a lower surface ofthe second light-reflective member.
 15. The light emitting deviceaccording to claim 10, wherein the light-transmissive resins and thelight-emitting element are bonded via a bonding member.
 16. The lightemitting device according to claim 10, wherein a sidewall of thethrough-hole has a protrusion.
 17. The light emitting device accordingto claim 16, wherein the protrusion is inclined toward the upper surfaceor the lower surface of the light-transmissive resin.
 18. The lightemitting device according to claim 10, wherein the firstlight-reflective member and the second light-reflective member eachinclude resin.
 19. The light emitting device according to claim 10,wherein a first light diffusion material is disposed in thelight-transmissive resin, and wherein a refractive index of the firstlight diffusion material at 25° C. is higher than a refractive index ofthe light-transmissive resin at 25° C.
 20. The light emitting deviceaccording to claim 19, wherein a portion of the first light diffusionmaterial is contained in a region other than a region in which thewavelength-conversion material is predominantly distributed.